Shelf



FIG. 1 is a perspective view of a shelf showing our new design;

FIG. 2 is a right side elevational view thereof, the left side being a mirror image of that shown;

FIG. 3 is a top plan view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is an enlarged vertical cross-sectional view thereof, taken in the direction of line 6--6 of FIG. 3. The broken line illustrations of a segment of a wall in FIG. 1 and of the bottom portion in FIGS. 4-6 are intended for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a shelf, as shown and described. 